The everolimus-eluting (Xience V) stent performs in everyday clinical practice much as it did in pre-approval trials, a real-world registry showed.

Action Points

The everolimus-eluting (XIENCE V) stent performs in everyday clinical practice much as it did in pre-approval trials.

There were no cases of late stent thrombosis when dual antiplatelet therapy was stopped after six months in either risk group. When dual antiplatelet therapy was interrupted within the first six months, the rate of stent thrombosis was 0% in the standard-risk group and 1.2% in the high-risk group.

The everolimus-eluting (XIENCE V) stent performs in everyday clinical practice much as it did in pre-approval trials, a real-world registry showed.

Rates of stent thrombosis and a composite of cardiac death or MI were similar among patients in the SPIRIT IV trial and among patients in a registry who would have met inclusion criteria for the trial, according to Mitchell Krucoff, MD, of the Duke Clinical Research Institute, and colleagues.

Those outcomes were more frequent in higher-risk patients (those who would have been excluded from the pre-approval trials), which is consistent with post-approval registries of other drug-eluting stents, the researchers reported in the December issue of JACC: Cardiovascular Interventions.

"Rigorously conducted, single-arm, postmarket condition-of-approval studies with prospective statistical analysis plans potentially serve both a regulatory and public health role by further informing pre-approval randomized evaluations with regard to residual safety issues, such as rare safety events and generalizability to the real-world practice of medicine," they wrote.

"Such information from the postmarket setting is critical to help balance safety concerns with the ability to encourage new device innovation."

That led to the approval of the everolimus-eluting stent in 2008. As a condition of the clearance, the FDA mandated a 5,000-patient postmarket study to further evaluate safety.

Krucoff and colleagues reported the one-year results of the study, called XIENCE V USA. It was a prospective, multicenter study of 5,054 unselected patients who received the stent; 37.1% would have met the inclusion criteria for the SPIRIT IV study (standard risk) and 62.9% carried a higher risk and would have been excluded (high risk).

The only patients who were excluded from the postmarket study were those unable to provide informed consent.

At one year, the rate of Academic Research Consortium (ARC)-defined definite and probable stent thrombosis -- one of the coprimary endpoints -- was 0.84% overall, 0.33% in the standard-risk group, and 1.12% in the high-risk group.

There were no cases of late stent thrombosis when dual antiplatelet therapy was stopped after six months in either risk group. When dual antiplatelet therapy was interrupted within the first six months, the rate of stent thrombosis was 0% in the standard-risk group and 1.2% in the high-risk group.

The rate of cardiac death or MI -- the second coprimary endpoint -- was 6.5% in the overall population, 3.8% in the standard-risk group, and 8% in the high-risk group. Most of those events were non-Q-wave MIs.

For the primary endpoints and most of the secondary endpoints, rates were comparable between the standard-risk group in the registry and the treatment arm of the SPIRIT IV trial, which suggests "that this study affords a reliable benchmark for understanding the safety of [the everolimus-eluting stent] in the context of real-world clinical practice," according to the authors.

However, rates were higher in the standard-risk patients in the registry than in the clinical trial for some of the secondary endpoints, including death (1.8% versus 1%, P=0.03) and cardiac death (0.9% versus 0.4%, P=0.05).

That "could be attributed to real-world, community-based clinical practice," Krucoff and colleagues wrote.

They noted that a limitation of the study is that it does not support head-to-head comparisons with other drug-eluting stents.

Krucoff reported receiving research grants from and doing moderate consulting for Abbott Vascular. His co-authors reported relationships with Abbott Vascular, Abbott, Boston Scientific, The Medicines Company, and Eli Lilly. Eight of the study authors are employees of Abbott Vascular and hold stock in the company.

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